ST25RU3993-HPEV oscillator

[NBand.1]

Good morning,

I'm designing a board based on ST25RU3993-HPEV development board. I'm finding some problems in understanding which oscillator to use. On both schematic and dm00717148 is said that only one oscillator between XO and TCXO should be used but on the (as bought from ST) board I have they are both connected, how is it possible? Did anyone has the same problem?

Thanks

[Bart Herse · Accepted solution]

Hi NBand.1,

thank you very much for this input!

Indeed there is an assembly mistake present on the reader, which does not notably alter the reader performance or function in any way.

In the schematic of ST25RU3993-HPEV, R54 and R55 are marked as not to be placed (DNP) but these components actually have been assembled by mistake.

For any application only one option should be used:

 We recommend to use a TCXO in applications for frequency stability and accuracy reasons.

To activate this option on the ST25RU3993-HPEV board, R54 and R55 must be removed.

This assembly mistake will be corrected for future builds of ST25RU3993-HPEV.

Cheers,

B